This specification relates to data communications.
Service providers utilize distributed networks to provide services to customers over large geographic areas. For example, communications companies utilize a distributed communications network to provide communications services to customers. Similarly, power companies utilize a network of power lines and meters to provide power to customers throughout a geographic region and receive data back about the power usage.
These service providers are dependent on proper operation of their respective networks to deliver services to the customers and receive data back regarding the services provided. For example, the service provider may want access to daily usage reports to efficiently bill their customers for the resources that are consumed or otherwise utilized by the customers. Therefore, it is important for data specifying resource utilization and other information to be reliably transmitted and/or received at specified intervals.
In power line communication networks, nodes in the network (e.g., meters) can provide updated information (e.g., power consumption information and/or node operating status information) by transmitting data over power lines. Generally, the meters utilize modulation techniques to encode multiple bits of data into the transmissions, thereby increasing the amount of data that can be provided over the power lines. For example, a node can use Quadrature Phase Shift Keying modulation to provide two bits of data. Similarly, a node can use 16 Quadrature Amplitude Modulation to provide four bits of data.
When modulation techniques (or other techniques) are used to encode data, error detection/correction techniques, such as forward error correction and automatic repeat request can be used to detect errors in the received data. For example, forward error correction can insert additional information (e.g., error-correcting code) into the data transmission to facilitate reconstruction of data that was most likely transmitted. Automatic repeat request inserts an error detection code that is used by the receiver to determine whether the received data is valid. When the data is invalid, the receiver requests retransmission of the data.
Each of these error detection/correction techniques require insertion of additional data (i.e., overhead) into the data stream, such that less bandwidth is available to transmit payload data (i.e., the data being reported by a node in the network). If the overhead transmitted through the network can be reduced, more data can be transmitted using the same bandwidth, and recovery of the payload data can be performed using less processing than that used to recover data that is transmitted with error detection/correction overhead data.